On Mon, Aug 18, 2014 at 09:59:49AM -0700, Brian C. Lane wrote: > On Mon, Aug 18, 2014 at 08:19:17AM +0200, Karsten Merker wrote: > > Hello, > > > > the following is a discussion from the Debian bugtracking system regarding > > Debian Bug#751704 > > (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=751704). > > It needs involvement from parted upstream, therefore I am forwarding it to > > bug-par...@gnu.org. > > Thanks for forwarding this. parted should only be clobbering these extra > sectors when a new disklabel is applied (eg. mklabel in the ui) which, I > think, is the appropriate thing to do. > > If you are operating on an existing disklabel and want to preserver a > boot loader in the space before the 1st partition you shouldn't be > calling ped_disk_new_fresh(). If you are creating a new disklabel then > any boot loader code should be installed after partitioning. > > I don't think parted needs any changes.
Hello, thanks for your swift reply. I fully understand your position, but unfortunately things on arm are fundamentally different from the PC world. U-Boot is more of a BIOS than a bootloader like GRUB; it is highly board specific and handles low-level stuff such as setting the IO pinmuxing for the specific board and configuring the DRAM controller. Without it, the board is completely dead from a user perspective. On a PC, the BIOS is always available in ROM/Flash even when all disk devices have been wiped and the user can still select some other device (such as the network, a CDROM drive or a USB memory stick) to boot from. On the arm systems we are talking about, there is no ROM BIOS and the u-boot image on the SD card (or on an eMMC chip) is the only way to interact with the system at all. The usual case is that the u-boot image is written raw onto the storage medium, i.e. there is no partition table or filesystem on it by default, so we need to create a new disklabel in the installer. You are fully right that normally a bootloader should be installed after partitioning. This works well for the case of a bootloader that uses universally available BIOS functions and is not hardware-specific, such as is the case on PCs. In the case of u-boot on the other hand, in PC-lingo we would have to provide the installer with the ability to flash the BIOS for every PC model on the market as part of the operating system installation, which is not feasible. We might be able to do that for a small selection of devices, but not for all of them --> we need to keep the u-boot image that is on the device even when creating a new disklabel, but we are unsure what is the best way to handle this. The approach in https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=751704#60 (setting PedDisk.needs_clobber to 0 before calling ped_disk_commit for specific devices) works in practice, but the question was whether it is ok for the calling application to fiddle around with the needs_clobber flag, or whether we should take some other approach. Kind Regards, Karsten -- Gem. Par. 28 Abs. 4 Bundesdatenschutzgesetz widerspreche ich der Nutzung sowie der Weitergabe meiner personenbezogenen Daten für Zwecke der Werbung sowie der Markt- oder Meinungsforschung. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
